Allocation of resources to a wireless device

ABSTRACT

There is provided mechanisms for allocating resources to a wireless device. A method is performed by a network node. The method comprises transmitting a control message in a search space to the wireless device, the search space comprising at least two groups of Control Channel Elements (CCEs), wherein one of the groups of CCEs comprises the control message. The method comprises transmitting information to the wireless device indicating at least one of the groups of CCEs comprising resources for the wireless device.

TECHNICAL FIELD

Embodiments presented herein relate to a method, a network node, a,computer program, and a computer program product for allocatingresources to a wireless device. Embodiments presented herein furtherrelate to a method, a wireless device, a computer program, and acomputer program product for receiving allocation of resources from anetwork node.

BACKGROUND

In communications networks, there may be a challenge to obtain goodperformance and capacity for a given communications protocol, itsparameters and the physical environment in which the communicationsnetwork is deployed.

For example, one parameter in providing good performance and capacityfor a given communications protocol in a communications network ispacket data latency. Latency measurements can be performed in all stagesof the communications network, for example when verifying a new softwarerelease or system component, and/or when deploying the communicationsnetwork and when the communications network is in commercial operation.

Shorter latency than previous generations of 3GPP radio accesstechnologies was one performance metric that guided the design of LongTerm Evolution (LTE). LTE is also now recognized by the end-users to bea system that provides faster access to internet and lower packetlatencies than previous generations of mobile radio technologies.

Packet latency is also a parameter that indirectly influences thethroughput of the communications network. Traffic using the HypertextTransfer Protocol (HTTP) and/or the Transmission Control Protocol (TCP)is currently one of the dominating application and transport layerprotocol suite used on the Internet. The typical size of HTTP basedtransactions over the Internet is in the range of a few 10's of Kilobyte up to 1 Mega byte. In this size range, the TCP slow start period isa significant part of the total transport period of the packet stream.During TCP slow start the performance is packet latency limited. Hence,improved packet latency can potentially improve the average throughput,at least for this type of TCP based data transactions.

Radio resource efficiency could also be positively impacted by packetlatency reductions. Lower packet data latency could increase the numberof transmissions possible within a certain delay bound; hence higherBlock Error Rate (BLER) targets could be used for the data transmissionsfreeing up radio resources potentially improving the capacity of thesystem.

The existing physical layer downlink control channels, Physical DownlinkControl Channel (PDCCH) and enhanced PDCCH (ePDCCH), are used to carryDownlink Control Information (DCI) such as scheduling decisions foruplink (UL; from device to network) and downlink (DL; from network todevice) and power control commands. Both PDCCH and ePDCCH are accordingto present communications networks transmitted once per 1 ms subframe.

3GPP TS 36.213 v13.1.1 lists examples of different (DCI) formats foruplink (UL) and downlink (DL) resource assignments. UL scheduling grantsuse either DCI format 0 or DCI format 4. The latter was added in the 3rdGeneration Partnership Project (3GPP) Release 10 (Rel-10) for supportinguplink spatial multiplexing

The existing way of operation, e.g. frame structure and controlsignalling, are designed for data allocations in subframes of a fixedlength of 1 ms, which may vary only in allocated bandwidth.Specifically, the current DCIs define resource allocations within theentire subframe, and are only transmitted once per subframe. Theexisting way of operation does not indicate how scheduling of UL and DLdata can be performed in short subframes, i.e., subframes shorter than 1ms.

Hence, there is a need for efficient communications using shortsubframes.

SUMMARY

An object of embodiments herein is to provide mechanisms forcommunications using short subframes.

According to a first aspect there is presented a method for allocatingresources to a wireless device. The method is performed by a networknode. The method comprises transmitting a control message in a searchspace to the wireless device, the search space comprising at least twogroups of Control Channel Elements (CCEs), wherein one of the groups ofCCEs comprises the control message. The method comprises transmittinginformation to the wireless device indicating at least one of the groupsof CCEs comprising resources for the wireless device.

According to a second aspect there is presented a network node forallocating resources to a wireless device. The network node comprisesprocessing circuitry. The processing circuitry is configured to causethe network node to transmit a control message in a search space to thewireless device, the search space comprising at least two groups ofCCEs, wherein one of the groups of CCEs comprises the control message.The processing circuitry is configured to cause the network node totransmit information to the wireless device indicating at least one ofthe groups of CCEs comprising resources for the wireless device.

According to a third aspect there is presented a network node forallocating resources to a wireless device. The network node comprisesprocessing circuitry and a computer program product. The computerprogram product stores instructions that, when executed by theprocessing circuitry, causes the network node to perform steps, oroperations. The steps, or operations, cause the network node to transmita control message in a search space to the wireless device, the searchspace comprising at least two groups of CCEs, wherein one of the groupsof CCEs comprises the control message. The steps, or operations, causethe network node to transmit information to the wireless deviceindicating at least one of the groups of CCEs comprising resources forthe wireless device.

According to a fourth aspect there is presented a network node forallocating resources to a wireless device. The network node comprises atransmit module configured to transmit a control message in a searchspace to the wireless device, the search space comprising at least twogroups of CCEs, wherein one of the groups of CCEs comprises the controlmessage. The network node comprises a transmit module configured totransmit information to the wireless device indicating at least one ofthe groups of CCEs comprising resources for the wireless device.

According to a fifth aspect there is presented a computer program forallocating resources to a wireless device, the computer programcomprising computer program code which, when run on processing circuitryof a network node, causes the network node to perform a method accordingto the first aspect.

According to a sixth aspect there is presented a method for receivingallocation of resources from a network node. The method is performed bya wireless device. The method comprises receiving a control message in asearch space from the network node, the search space comprising at leasttwo groups of CCEs wherein one of the groups of CCEs comprises thecontrol message. The method comprises receiving information from thenetwork node indicating at least one of the groups of CCEs comprisingresources for the wireless device.

According to a seventh aspect there is presented a wireless device forreceiving allocation of resources from a network node. The wirelessdevice comprises processing circuitry. The processing circuitry isconfigured to cause the wireless device to receive a control message ina search space from the network node, the search space comprising atleast two groups of CCEs wherein one of the groups of CCEs comprises thecontrol message. The processing circuitry is configured to cause thewireless device to receive information from the network node indicatingat least one of the groups of CCEs comprising resources for the wirelessdevice.

According to an eighth aspect there is presented a wireless device forreceiving allocation of resources from a network node. The wirelessdevice comprises processing circuitry and a computer program product.The computer program product stores instructions that, when executed bythe processing circuitry, causes the wireless device to perform steps,or operations. The steps, or operations, cause the wireless device toreceive a control message in a search space from the network node, thesearch space comprising at least two groups of CCEs wherein one of thegroups of CCEs comprises the control message. The steps, or operations,cause the wireless device to receive information from the network nodeindicating at least one of the groups of CCEs comprising resources forthe wireless device.

According to a ninth aspect there is presented a wireless device forreceiving allocation of resources from a network node. The wirelessdevice comprises a receive module configured to receive a controlmessage in a search space from the network node, the search spacecomprising at least two groups of CCEs wherein one of the groups of CCEscomprises the control message. The wireless device comprises a receivemodule configured to receive information from the network nodeindicating at least one of the groups of CCEs comprising resources forthe wireless device.

According to a tenth aspect there is presented a computer program forreceiving allocation of resources from a network node, the computerprogram comprising computer program code which, when run on processingcircuitry of a wireless device, causes the wireless device to perform amethod according to the sixth aspect.

According to an eleventh aspect there is presented a computer programproduct comprising a computer program according to at least one of thefifth aspect and the tenth aspect and a computer readable storage mediumon which the computer program is stored. The computer readable storagemedium can be a non-transitory computer readable storage medium.

Advantageously these methods, these network nodes, these wirelessdevices, and these computer programs provides efficient communicationsusing short subframes.

Advantageously these methods, these network nodes, these wirelessdevices, and these computer programs allow unused resources (e.g., onshort PDCCH) to be utilized (e.g., used for short PDSCH), in someembodiments without the wireless device having to share the same searchspace with another wireless device.

It is to be noted that any feature of the first, second, third, fourth,fifth, sixth seventh, eight, ninth, tenth and eleventh aspects may beapplied to any other aspect, wherever appropriate. Likewise, anyadvantage of the first aspect may equally apply to the second, third,fourth, fifth, sixth, seventh, eight, ninth, tenth, and/or eleventhaspect, respectively, and vice versa. Other objectives, features andadvantages of the enclosed embodiments will be apparent from thefollowing detailed disclosure, from the attached dependent claims aswell as from the drawings.

Generally, all terms used in the claims are to be interpreted accordingto their ordinary meaning in the technical field, unless explicitlydefined otherwise herein. All references to “a/an/the element,apparatus, component, means, step, etc.” are to be interpreted openly asreferring to at least one instance of the element, apparatus, component,means, step, etc., unless explicitly stated otherwise. The steps of anymethod disclosed herein do not have to be performed in the exact orderdisclosed, unless explicitly stated.

BRIEF DESCRIPTION OF THE DRAWINGS

The inventive concept is now described, by way of example, withreference to the accompanying drawings, in which:

FIG. 1 is a schematic diagram illustrating a communication networkaccording to embodiments;

FIGS. 2, 3, 4, and 5 are flowcharts of methods according to embodiments;

FIGS. 6-16 schematically illustrate search spaces in short TTIsaccording to embodiments;

FIG. 17 is a schematic diagram showing functional units of a networknode according to an embodiment;

FIG. 18 is a schematic diagram showing functional modules of a networknode according to an embodiment;

FIG. 19 is a schematic diagram showing functional units of a wirelessdevice according to an embodiment;

FIG. 20 is a schematic diagram showing functional modules of a wirelessdevice according to an embodiment; and

FIG. 21 shows one example of a computer program product comprisingcomputer readable means according to an embodiment.

DETAILED DESCRIPTION

The inventive concept will now be described more fully hereinafter withreference to the accompanying drawings, in which certain embodiments ofthe inventive concept are shown. This inventive concept may, however, beembodied in many different forms and should not be construed as limitedto the embodiments set forth herein; rather, these embodiments areprovided by way of example so that this disclosure will be thorough andcomplete, and will fully convey the scope of the inventive concept tothose skilled in the art. Like numbers refer to like elements throughoutthe description. Any step or feature illustrated by dashed lines shouldbe regarded as optional.

FIG. 1 is a schematic diagram illustrating a communications network 100where embodiments presented herein can be applied. The communicationsnetwork 100 comprises at least one network node 200. The functionalityof the network node 200 and how it interacts with other entities, nodes,and devices in the communications network 100 will be further disclosedbelow. The communications network 100 further comprises at least oneradio access network node 140. The at least one radio access networknode 140 is part of a radio access network 110 and operatively connectedto a core network 120 which in turn is operatively connected to aservice network 130. The at least one radio access network node 140provides network access in the radio access network 110. A wirelessdevice 300 a, 300 b served by the at least one radio access network node140 is thereby enabled to access services and exchange data with thecore network 120 and the service network 130.

Examples of wireless devices 300 a, 300 b include, but are not limitedto, mobile stations, mobile phones, handsets, wireless local loopphones, user equipment (UE), smartphones, laptop computers, tabletcomputers, network equipped sensors, wireless modems, and Internet ofThings devices. Examples of radio access network nodes 120 include, butare not limited to, radio base stations, base transceiver stations,NodeBs, evolved NodeBs, access points, and access nodes. As the skilledperson understands, the communications network 100 may comprise aplurality of radio access network nodes 120, each providing networkaccess to a plurality of wireless devices 300 a, 300 b. The hereindisclosed embodiments are no limited to any particular number of networknodes 200, radio access network nodes 120 or wireless devices 300 a, 300b.

The wireless device 300 a, 300 b accesses services and exchanges datawith the core network 120 and the service network 130 by transmittingdata in packets to the core network 120 and the service network 130 andby receiving data in packets from the core network 120 and the servicenetwork 130 via the radio access network node 140.

Packet latency has above been identified as degrading networkperformance. One area to address when it comes to packet latencyreductions is the reduction of transport time of data and controlsignalling, by addressing the length of a transmission time interval(TTI). In LTE release 8, a TTI corresponds to one subframe (SF) oflength 1 millisecond. One such 1 ms TTI is constructed by using 14 OFDMor SC-FDMA symbols in the case of normal cyclic prefix and 12 OFDM orSC-FDMA symbols in the case of extended cyclic prefix.

The embodiments disclosed herein relate to mechanisms for allocatingresource to a wireless device 300 a. In order to obtain such mechanismsthere is provided a network node 200, a method performed by the networknode 200, a computer program product comprising code, for example in theform of a computer program, that when run on processing circuitry of thenetwork node 200, causes the network node 200 to perform the method.

The embodiments disclosed herein further relate to mechanisms forreceiving allocation of resource from a network node 200. In order toobtain such mechanisms there is further provided a wireless device 300a, 300 b, a method performed by the wireless device 300 a, 300 b, and acomputer program product comprising code, for example in the form of acomputer program, that when run on processing circuitry of the wirelessdevice 300 a, 300 b, causes the wireless device 300 a, 300 b to performthe method.

According to embodiment disclosed herein the TTIs are shortened byintroducing shortened subframes (below denoted short subframes). With ashort TTI, the subframes can be decided to have any duration in time andcomprise resources on a number of OFDM or SC-FDMA symbols within a 1 mssubframe. As one example, the duration of a short subframe may be 0.5ms, i.e., seven OFDM symbols or SC-FDMA symbols for the case with normalcyclic prefix.

As mentioned, one way to reduce latency is to reduce the transmissiontime interval (TTI), and instead of assigning resources with a timeduration of 1 ms, there is then a need to assign resources with shorterduration such as a number of OFDM symbols or SC-FDMA symbols. Thisimplies a need for device specific control signalling that enablesindication of such short scheduling assignments.

Using scheduling with 1 ms TTIs, the wireless devices 300 a, 300 b areallocated frequency resources based on, e.g., bitmaps in DCI fieldsidentifying used resource blocks. As the TTI length is shortened, thismay lead to an increased signaling overhead if the allocation isspecified several times per subframe. Having a grant only to a singlewireless device 300 a, 300 b per such short TTI will limit the overhead.It might be further beneficial to share the frequency resources within ashort TTI between several wireless device 300 a, 300 b, while limitingthe amount of control overhead.

A wireless device 300 a, 300 b can be configured for short TTI operationby being assigned a group short TTI Radio Network Temporary Identifier(RNTI). The wireless device 300 a, 300 b could then searches the commonto search space (CSS) of the PDCCH for slow grants (comprising a slowDownlink Control Information (DCI) message) scrambled with the short TTIRNTI. This slow grant comprises the frequency allocation for a downlink(DL) and an uplink (UL) short TTI frequency band to be used for shortTTI operation. After decoding such a slow grant the wireless device 300a, 300 b is in short TTI operation and can extend its search space to anin-band control channel, also defined by the slow grant.

A DCI message is encoded onto a number of Control Channel Elements(CCEs) in the PDCCH region of the DL subframe. The wireless device 300a, 300 b searches both in a CSS and a device-specific search space (USS;where U is short for UE as in User Equipment) in the PDCCH for differentCCE aggregation levels (AL). The number PDCCH candidates of differentsizes in LTE are given in Table 9.1.1-1 in 3GPP TS 36.213 v13.1.1.According to this table there are 22 PDCCH candidates to be monitored bythe wireless device 300 a, 300 b, and with 2 different DCI sizes definedfor each transmission mode, there are a total of 44 possibilities thatthe wireless device 300 a, 300 b has to try with blind decoding.

In legacy LTE the wireless device 300 a, 300 b monitors a predefined USSfor the PDCCH. With the introduction of a new in-band control channel(below denoted short PDCCH) the number of blind decoding attempts willincrease for a wireless device 300 a, 300 b in short TTI operation. Atthe same time this wireless device 300 a, 300 b need the USS for anylegacy TTI UL grants or DL allocations.

The term short TTI (sTTI) is used to denote a TTI of a short subframe.The short subframe can have a shorter duration in time than 1 ms. Theshort TTI can be defined as being shorter than the interval between twoconsecutive PDCCH transmissions (as being transmitted once every 1 ms).To achieve latency reduction the networks node 200 can thus beconfigured to schedule data on short timeframes, such as at short TTIlevel.

The control channel will take up a large percentage of the resourceswhen the TTI becomes smaller with the introduction of shorter TTIs indownlink. Reducing the overhead of control channel can result in aperformance increase when short TTIs are used. The herein disclosedembodiments enable efficient minimization of the overhead of the controlchannel by structuring the total available search space across wirelessdevice 300 a, 300 b so that the signaling to the device 300 a, 300 b toindicate unused CCEs is minimized. This is achieved by the introductionof a CCE group and associated signaling to indicate whether or not aspecific CCE group is utilized or not.

FIGS. 2 and 3 are flow charts illustrating embodiments of methods forallocating resources to a wireless device 300 a as performed by thenetwork node 200. FIGS. 4 and 5 are flow charts illustrating embodimentsof methods for receiving allocation of resources from a network node 200as performed by the wireless device 300 a, 300 b. The methods areadvantageously provided as computer programs 1020 a, 1020 b (see below).

Reference is now made to FIG. 2 illustrating a method for allocatingresources to a wireless device 300 a as performed by the network node200 according to an embodiment.

S104: The network node 200 transmits a control message in a search spaceto the wireless device 300 a. The search space comprises at least twogroups of CCEs. One of the groups of CCEs comprises the control message.

S106: The network node 200 transmits information to the wireless device300 a indicating that at least one of the groups of CCEs comprisesresources for the wireless device 300 a.

Embodiments relating to further details of allocating resources to awireless device 300 a will now be disclosed.

Reference is now made to FIG. 3 illustrating methods for allocatingresources to a wireless device 300 a as performed by the network node200 according to further embodiments. It is assumed that steps S104,S106 are performed as disclosed with reference to FIG. 2 and a repeateddescription of these steps is therefore omitted. The method features maybe carried out in any order.

According to an embodiment the network node 200 configures the wirelessdevice 300 a with the size of the CCEs. Hence, according to anembodiment the network node 200 is configured to perform step S102:

S102: The network node 200 transmits configuration informationindicating a size of each group of CCEs. The configuration informationcan be transmitted in radio resource control (RRC) signalling, or in aPhysical Downlink Control Channel (PDCCH).

If the size is set in PDCCH, it can be determined according to the knownnumber of active wireless devices 300 a, 300 b served by the networknode 200 and their required aggregation level (AL). Especially, if thereare relatively few wireless devices 300 a, 300 b, then the short PDCCHregion can be reduced to include fewer positions for a given AL. Analternative to this approach is that the size of the groups of CCEs isfixed according to a specification. Each group of CCEs could correspondto a short PDCCH region.

Reference is now made to FIG. 4 illustrating a method for receivingallocation of resources from a network node 200 as performed by thewireless device 300 a, 300 b according to an embodiment.

As disclosed above, the network node 200 in step S104 transmits acontrol message to the wireless device 300 a. It is assumed that thewireless device 300 a receives this control message. Hence, the wirelessdevice 300 a, 300 b is configured to perform step S206:

S206: The wireless device 300 a receives a control message in a searchspace from the network node 200. The search space comprises at least twogroups of CCEs. One of the groups of CCEs comprises the control message.

As disclosed above, the network node 200 in step S106 transmitsinformation to the wireless device 300 a. It is assumed that thewireless device 300 a receives this information. Hence, the wirelessdevice 300 a, 300 b is configured to perform step S208:

S208: The wireless device 300 a receives information from the networknode 200, the information indicates that at least one of the groups ofCCEs comprises resources for the wireless device 300 a, 300 b. Forexample, the information indicates to the wireless device which of thegroups comprises resources for the wireless device. The wireless devicedetermines the group comprising resources (e.g. the group comprising arelevant a control message or data message) from the receivedindication. The determination of the group of CCEs provides for thewireless device to efficiently find (i.e. decode) the resources for thewireless device (e.g. containing a control message or data).

Reference is now made to FIG. 5 illustrating methods for receivingallocation of resources from a network node 200 as performed by thewireless device 300 a, 300 b according to further embodiments. It isassumed that steps S206, S208 are performed as disclosed with referenceto FIG. 4 and a repeated description of these steps is thereforeomitted.

As disclosed above, the network node 200 in an embodiment configures thewireless device 300 a. Hence, according to an embodiment the wirelessdevice 300 a, 300 b is configured to perform step S202:

S202: The wireless device 300 a, 300 b receives configurationinformation indicating a size of each group of CCEs. As disclosed above,the configuration information can be received in RRC signalling, or in aPDCCH.

Further, the wireless device 300 a, 300 b can receive furtherinformation and hence according to an embodiment the wireless device 300a, 300 b is configured to perform step S204:

S204: The wireless device 300 a, 300 b receives configurationinformation, for example, indicating a start position of the resourceswithin the groups of CCEs.

Embodiments relating to further details of allocating resources to awireless device 300 a as performed by the network node 200 and receivingallocation of resources from a network node 200 as performed by thewireless device 300 a, 300 b will now be disclosed.

Several groups of CCEs can be defined. Each such group includes at leastone position per AL. One position can be reused for several ALs. A CCEgroup thus contains sufficient resources for the maximum aggregationlevel.

FIG. 6 illustrates the concept of a CCE group. The CCE group maycomprise a message comprising one of a plurality of possible aggregationlevels. The CCE group are CCE resources (e.g. physical resources) whichmay be used for control or data messages to/from a wireless device andthe radio access network 110. The CCE group does not contain differentmessages containing all the plurality of different aggregation levels,but may contain one or more message (e.g. control message), each messagehaving an aggregation level. A remainder of resources (illustrated asspace to the right of the hashed message), is unused by a controlmessage. For instance, if AL 2 of a CCE group is used for sending acontrol message (e.g. the fast DCI), some resources remain unused inthis CCE group. If AL 4 is used instead, all resources of the CCE groupare used. In the following it will be demonstrated how to exploit theunused resources for data transmission. Although the CCE group isdefined up to AL 4, the herein disclosed embodiments allow the CCE groupto be extended to any AL, e.g. for example up to AL 8 or 16. The maximumAL can also be reduced in size down to AL 2.

A plurality of CCE groups is defined in the resources of a controlchannel (e.g. PDCCH). The CCE group may be considered as a group ofresources (i.e. CCEs or physical layer resources) which can accommodatea message (e.g. a control message) up to a maximum aggregation level.The CCE group may alternatively accommodate one or more message (e.g. acontrol message) of a smaller aggregation level. In some examples, themessage (e.g. a control message) for different aggregation levels startsat a same position, i.e. position is independent of aggregation level.

There are multiple ways of mapping CCEs to individual resource elements.One way is to reuse the mapping from the control channel (e.g. PDCCH),but contained within the short TTI bandwidth. Another way is to allocatethe CCEs to REGs that are assigned within a limited set of PRBs and notspread over the whole allocated frequency bandwidth. An example of suchan allocation is EPDCCH. For short TTI operation it may however bebeneficial to spread out the short PDCCH more in frequency than EPDCCHand also to allow the short PDSCH on the same frequency resources withinthe short TTI. However the short PDCCH allocation can still be keptlocalized in the sense that it is only allocated to a limited set ofPRBs and not randomized over a large frequency bandwidth.

According to an embodiment, the wireless device 300 a, 300 b and networknode 200 use a single start position for messages of all aggregationlevels in a CCE group. As such, messages with different AL start at asame position in the search space for a particular CCE group. In thiscase, the search space is common to all wireless devices 300 a, 300 b.

FIG. 7 gives an example of the control channel (e.g. short PDCCH) searchspace of the instant embodiment. The search space is comprises 4 CCEgroups, each containing a message having 3 possible ALs. Even though theCCE groups are drawn each one after another (e.g. distributed in a timedomain), their physical resources can be distributed over the frequencydomain (i.e., there may be a gap in between the resources of CCE group nand CCE group n+1, where n is an integer).

To detect a control message (e.g. short PDCCH), a wireless device 300 a,300 b may test all CCE groups for all ALs. Alternatively, the wirelessdevice 300 a, 300 b could test only some of the ALs in each CCE groupsif the network node 200 signaled to the wireless device 300 a, 300 binformation about a reduced set of ALs to test. Alternatively, thewireless device 300 a, 300 b could test all ALs in only some of the CCEgroups if the network node 200 signals this to the wireless device 300a, 300 b. This means that even though the search space is common to morethan one wireless device 300 a, 300 b, the network node 200 can reducethe search space on a device-specific basis.

Resource Usage Optimization:

As described above, if a low AL is used for the fast DCI, some resourcesof the CCE group remain unused. In the an embodiment, the wirelessdevice 300 a, 300 b may determine that unused resources in the CCE groupwhere its control message (e.g. specific to that wireless device 300 a,e.g. fast DCI) was sent with low AL (i.e. less than maximum AL) are usedfor its own data message or allocation (e.g. short PDSCH). For example,if AL 2 is used for the fast DCI and the CCE group contains 4 CCEs, tworemaining CCEs can be used for the wireless device 300 a, 300 b shortPDSCH REs.

The resources used for short PDSCH can for example be all the resourcesavailable within the own CCE group or the resources that map to the samefrequency allocation for which short PDSCH is allocated on. To furtheroptimize the unused short PDCCH resources, a bitmap of x−1 bits can besignaled to the wireless device 300 a, 300 b in the device-specificcontrol message (e.g. fast DCI), where x is the number of CCE groups inthe short PDCCH search space. The bitmap is an example of informationtransmitted to the wireless device to indicate resources for thewireless device. Such a bitmap could inform the wireless device 300 a,300 b that resources in other CCE groups can be used for its own dataresources, for example, downlink data allocation (e.g. short PDSCH).

FIG. 8 schematically illustrates an example with a search space of 4 CCEgroups. A control message (e.g. fast DCI) is received in CCE group 3 fora first wireless device denoted UE1. UE1 may be configured to determinethat the remaining resources in CCE group 3 which are not occupied bythe fast DCI are used for short data for UE1 (e.g. PDSCH). UE1 may beconfigured to make this determination without receiving any furthersignalling. The decoded control message (e.g. fast DCI) could comprise abitmap with value 111. The wireless device 300 a, 300 b could thendetermine that the resources in CCE group 1, 2, and 4 are used for itsdata (e.g. short PDSCH). Other ways or methods of indicating theinformation other than using a bitmap can be used to signal theinformation to wireless devices 300 a, 300 b, to use the resources inthe same or different CCE group.

In the above example, the resource usage is optimized by using unusedresources of a group (empty CCEs) for the short PDSCH to increase thecapacity for downlink data transmissions. Using empty CCEs for thedownlink data transmissions (e.g. short PDSCH) also indicates that powerneeds to be allocated to these CCEs, which might imply that no powerboosting can be performed on the short PDCCH to further enhance theshort PDCCH transmissions. Therefore, there is a tradeoff on how to usethe empty CCEs; to increase the capacity for data transmission or toenhance the short PDCCH transmission. The empty CCEs can also be used tocoordinated inter-cell interference.

In the above example the network node 200 has only scheduled a singlewireless device 300 a, 300 b on a control channel for operating with ashort TTI (e.g. short PDCCH). However the resources used for thedownlink data transmission e.g. short PDSCH within the control channelregion (e.g. short PDCCH region) can, for example, be all the resourcesavailable resources that are indicated to be free, or, the resourcesthat map to the same frequency allocation for which the data channel(e.g. short PDSCH) is allocated on and also indicated as free.

FIG. 9 illustrates an example of control and data channel allocations,for example, when operating in a sTTI operation (e.g. short PDCCH andshort PDSCH allocation). FIG. 9(a) shows use of data on resources thatmap to the same frequency allocation for which the data channel. FIG.9(b) shows use by a wireless device of all the resources (i.e. availableresources) that are indicated to be free for data, in both the datachannel and the unused resources of the control channel, in a short TTIoperation.

References to short PDCCH may be considered as an example of a controlchannel, and references to short PDSCH may be considered as an exampleof a data channel, downlink data channel or downlink data transmission,in a short TTI operation. The short refers to operation with a short TTI(less than one subframe or 1 ms). References to a fast DCI may beconsidered as an example of a control message which is specific to aparticular wireless device. A slow DCI may be considered as an exampleof a control message which is common to a plurality of wireless devicesand/or provides information on the frequency band used for short TTIoperation.

In FIG. 9, the short PDCCH search space is composed of 4 CCE groups of 4CCEs each. Each box labelled as sPDCCH search space indicates a CCE, andthe grid of 16 boxes (CCEs) is the control channel search spacecomprising control information. The search space extends in thefrequency domain and the time domain. In this example, the wirelessdevice 300 a (UE1) uses AL 2 of CCE group 3, so two CCEs of group 3 areoccupied by the downlink fast DCI of UE1. These CCEs are representedwith dotted boxes and are distributed over the entire sPDCCHtime-frequency region according to a mapping function that is known tothe wireless device 300 a and the network node 200.

The downlink fast DCI of wireless device 300 a sent in a short PDCCHindicates a short PDSCH allocation for wireless device 300 a identifiedby a hatched region in FIG. 9(a). With a bitmap in the fast DCI withvalue 111, the wireless device 300 a could use all unoccupied resourcesof the short PDCCH search space. In a first case, since the short PDSCHfrequency allocation for the wireless device 300 a does not cover theentire short PDCCH search space, the wireless device 300 a could assumethat only the allocated frequency resources that overlap with shortPDCCH resources signaled as free are used for its short PDSCH.

Thus, in FIG. 9(a), only the short PDCCH resources that overlap with thehatched region and are signaled as free in the bitmap are used for theshort PDSCH, i.e. for data. In a second case, the wireless device 300 aassumes that the short PDSCH frequency allocation is extended (e.g.extended in frequency) with the short PDCCH resources signaled as freein the bitmap. This results in the hatched region shown in FIG. 9(b). Itis possible to achieve the hatched region in FIG. 9(b) using the firstcase based on scheduling from the network node 200. The network node 200then has to make sure to schedule the short PDSCH so that it completelyoverlaps with the short PDCCH region in the first few symbols of thesTTI.

This embodiment is efficient for data resources left unused by shortPDCCH in the short PDCCH search space in case wireless devices 300 a,300 b in downlink are scheduled (by a fast DCI message for downlink datatransmission).

FIG. 10 illustrates a scenario where the fast DCI comprises a grant foruplink data transmission, such as in CEE group 1 for the wireless devicedenoted UE 2 and CCE group 2 for the wireless device denoted UE3. Theresources left empty in CCE group 1 and group 2 cannot be exploited byUE2 and UE3 since they have uplink traffic and not downlink traffic. CCEgroup 1 and CCE group 2 cannot either be signaled as empty to thewireless device denoted UE1 which has downlink traffic if a bitmap ofx−1 bits is used for the signaling.

To avoid this issue, more information can be provided to the wirelessdevice 300 a, 300 b, e.g. more bits can be added to the bitmap. In orderto fully optimize the resource usage, a bitmap of (z−1)·n bits can beneeded, where z is the number of CCE groups, and n is the smallest valuesuch that 2n is larger than or equal to the number of supported ALs.

Consider the CCE group defined in FIG. 6, a bitmap table can be definedto indicate the usage of the CCEs for sPDCCH within this group as inTable 1. Based on Table 1, by signaling a bitmap of “101011” to UE1, theempty CCEs in CCE group 1 and CCE group 2 can also be used by UE1 fordownlink data transmission.

TABLE 1 Bitmap table for example in FIG. 6. Usage of CCEs indicator bitfield Meaning 00 CCEs in AL₄ defined in this CCE group are used forshort PDCCH, no CCE is left for short PDCCH 01 CCEs in AL₁ defined inthis CCE group are used for short PDCCH, the rest of the short PDCCH canbe used for short PDCCH 10 CCEs in AL₂ defined in this CCE group areused for short PDCCH, the rest of the CCEs can be used for short PDCCH11 No CCEs are used for short PDCCH, and all CCEs in this CCE group canbe used for short PDCCH

According to an embodiment, several start positions are defined for atleast some of the ALs per CCE group. For example, the relatively low ALshave a plurality of start positions for a control message defined. FIG.11 shows an example with two possible start positions for AL1 and AL 2for each CCE group. In this example, a second start position is the samefor a plurality of aggregation levels (e.g. AL1 and AL2).

According to this embodiment, active wireless devices 300 a, 300 b areconfigured with non-overlapping start positions. For instance, a firstwireless device 300 a can be configured with positions 1 whilst a secondwireless device 300 b can be configured with the positions 2 in each CCEgroup. The same position for AL 4 is used for both wireless devices 300a, 300 b, assuming that AL 4 is the maximum available AL. This isillustrated in FIG. 11. The configuration of which positions to use caneither be signaled using a higher layer signalling (e.g. over RRC) orover PDCCH (e.g. using a slow DCI message). The configuration can besignaled over PDCCH in order to update the usage of positions 1 and 2based on the active wireless devices 300 a, 300 b at a given time.

All positions represented in FIG. 11 are part of the common searchspace. All wireless devices 300 a, 300 b know the existence of allpositions, but at a given time they are configured to test only one oronly a subset of positions for the control message, e.g. “positions 1”or only the “positions 2”. More than one wireless device 300 a, 300 bcan be configured to monitor “positions 1” as well. For instance, thedownlink assignment for one wireless device 300 a can be signaled usingposition 1 of CCE group 3 while the downlink assignment for anotherwireless device 300 b can be signaled using position 1 of CCE group 4.Both these wireless devices 300 a, 300 b will need to test all positions1 in all CCE groups to find their assignment (unless the network node200 informs about a reduced set). The wireless device is configured todetermine the position in a CCE group by signalling, based on anotherreceived message or using a predetermined value.

Resource usage optimization: Similarly as in the above embodiment, ainformation (e.g. a bitmap) can be signaled to the wireless device 300a, 300 b to inform about the usage of other CCE groups for its shortPDSCH. In the instant embodiment the bitmap could also include furtherinformation (e.g. an additional) bit for the CCE group used for the fastDCI message for the wireless devices 300 a, 300 b. This additional bitthen indicates if the remaining resources of the CCE group where thefast DCI was decoded is used for its short PDSCH.

FIG. 12 gives an example assuming 4 CCE groups and that the wirelessdevice denoted UE1 has received its fast DCI message in CCE group 3 andthat the fast DCI message comprises a bitmap with value 1100. As notedabove, some other way than using a bitmap can be used to signal theinformation to wireless devices 300 a, 300 b to use the resources in thesame or different CCE group. The wireless device denoted UE1 should thusassume that the resources in CCE group 1 and 2 are used for its shortPDSCH whilst resources in CCE groups 3 and 4 are not. The remainingresources in CCE group 3 used for sending the fast DCI message to UE1are used for sending a fast DCI message to a different wireless device.The wireless device denoted UE2 has received its fast DCI in CCE group 3and it comprises a bitmap with value 0001.

In the above example the network node 200 has only scheduled a singlewireless device 300 a, 300 b on short PDCCH. However the resources usedfor short PDSCH within the short PDCCH region can, for example, be allthe resources available resources that are indicated to be free or theresources that map to the same frequency allocation for which shortPDSCH is allocated on and also indicated as free.

One way to reduce the bitmap size is to configure each wireless device300 a, 300 b to monitor only a subset of the CCE groups. For example,one wireless device 300 a can be configured to test only CCE group 1 and2 and another wireless device 300 b can be configured to test only CCEgroup 3 and 4. The downlink assignment for wireless device 300 a can besignaled using position 1 of CCE group 1 while the downlink assignmentfor wireless device 300 b can be signaled using position 1 of CCE group4. In this case, the empty CCEs in group 1 and 2 are used for the shortPDSCH for wireless device 300 a, and the empty CCEs in group 3 and 4 areused for the short PDSCH for wireless device 300 b, without a need of abitmap.

An embodiment enables the fast DCI transmission for wireless devices 300a, 300 b scheduled in uplink such that these wireless devices 300 a, 300b do not occupy a dedicated CCE group. As described in the previousembodiment, a CCE group used only for uplink grant prevents the usage ofthe remaining resources of this CCE group for the short PDSCH of otherwireless devices.

In FIG. 13, the wireless device denoted UE1 is scheduled in downlink,whilst the wireless devices denoted UE2 and UE3 are scheduled in uplink.UE 2 and UE 3 are configured such that UE2 uses positions 1 in the CCEgroup whilst UE 3 uses positions 2. In this way, the uplink fast DCImessage for UE 2 and UE3 can be sent in the same CCE group withoutoverlapping if a low AL is used. The unused resources of the short PDCCHsearch space are thus better exploited for the downlink wireless device,i.e., UE1, in FIG. 13 than in FIG. 10.

The instant embodiment can be extended to include even more startpositions per CCE group. This is shown in FIG. 14. Consequently, theconfiguration of which position to use would need a higher number ofbits. In this example, start positions may depend on the aggregationlevel.

An alternative to FIGS. 11 and 14, where the start positions areidentical for all CCE groups, and where these start positions might needto be explicitly configured, is shown in FIG. 15. FIG. 15 illustrates anexample where start positions for different wireless devices 300 a, 300b are different between different CCE groups, in order to allowarbitrary combinations of two wireless devices 300 a, 300 b to be sentfast DCI in the same CCE group. Only AL 2 shown in this example. In thisexample, any two wireless devices 300 a, 300 b can receive fast DCI inat least one common CCE group, without explicit control signaling.

In FIG. 15, at least two CCE groups can be found allowing anycombination of two different wireless devices 300 a, 300 b to receiveDCI messages. One would be the minimum requirement. In FIG. 16 adifferent configuration is presented, allowing the same wireless device300 a, 300 b to receive DCI messages in the same CCE group.

FIG. 16 illustrates and example similar to FIG. 13, but where it ispossible to place two fast DCI messages for the same wireless device 300a, 300 b in the same CCE group. This can be beneficial if it is desiredto transmit two AL2 messages to the same wireless device 300 a, 300 b.To keep the total number of positions low, each wireless device 300 a,300 b can here only read CCE messages in three of the four CCE groups.This would then increase the number of positions, as e.g. the wirelessdevices denoted UE1 and UE2 now searches for two starting positions inCCE group 1. To limit the total number of start positions for eachwireless device 300 a, 300 b, in this example, each wireless device 300a, 300 b is configured to only search a subset of the CCE groups, e.g. 3out of the 4 CCE groups. It is still possible to find combinationsbetween any two wireless devices 300 a, 300 b in at least one CCE group,compared to before the removal, where at least two CCE groups could befound for each combination of different wireless devices 300 a, 300 b(as in FIG. 15).

According to a further embodiment it is provided that if the wirelessdevice 300 a, 300 b can determine (e.g. make an assumption) the usedaggregation level across CCE groups it is possible for the wirelessdevice 300 a, 300 b when scheduled in downlink to utilize more of theavailable resources. For example the wireless device 300 a, 300 b can besignaled the bit field indicating whether or not each corresponding CCEgroup is free. Using this information together with knowing the AL thewireless device 300 a, 300 b decoded its own DL assignment on, thewireless device 300 a, 300 b can then utilize the corresponding unusedresources for short PDSCH if assigned to do. The assignment can be basedon the indication that the resources are free (i.e. unused by anotherwireless device) or that they are free and within the allocatedfrequency resources for short PDSCH.

A summary of the above disclosed embodiments applicable to both themethods performed by the network node 200 and the wireless device 300 a,300 b will now be provided.

According to an embodiment the information only indicates groups of CCEsnot comprising the control message. Further aspects of this embodimentwill now be disclosed.

The same wireless device 300 a can receive two DCI messages in the sameCCE group. Hence, according to an embodiment the control message isprovided in one of the groups of CCEs, and a further control message forthe wireless device also is provided in the above-specified one of thegroups of CCEs.

A reduction in number of starting positions can be achieved by eachwireless device 300 a, 300 b being configured to only monitor a reducednumber of CCEs. Hence, according to an embodiment only less than all ofthe groups of CCEs are allowed to comprise said control message and/orsaid resources for the wireless device.

As disclosed above, the information transmitted in step S106 andreceived in step S208 can be defined by a bitmap. Such a bitmap couldindicate one or more CCE groups comprising a data message and/or one ormore CCE groups comprising a control message for the wireless device 300a.

According to some aspects there are different ALs of CCEs in each group.Hence, according to an embodiment each group of CCEs has a size tocontain CCEs of at least two aggregation levels, AL. One of the at leasttwo ALs can be a maximum AL.

There are different types of resources. According to an embodiment theresources are downlink resources. The downlink resources could beresources used for a short Physical Downlink Shared Channel (PDSCH).

For example, the wireless device 300 a could determine that resources ina CCE group contains the control message for the wireless device 300 a,and that resources which are unused for the control message comprise anallocation for a data message. The allocation for a data message couldbe a downlink assignment (i.e., a short PDSCH).

There are different types of information transmitted in step S106 andreceived in step S208. According to an embodiment this informationcomprises an indication of at least one of the groups of CCEs comprisingthe control message and/or a data message for the wireless device 300 a.

There are different types of control messages transmitted in step S104and received in step S106. According to an embodiment the controlmessage is a downlink assignment or an uplink grant. For example thecontrol message could be Downlink Control Information (DCI), and/or thesearch space could be a control channel comprising CCEs, and/or thecontrol channel could be a PDCCH. The control message transmitted instep S104 and received in step S206 can be specific to the wirelessdevice 300 a.

Resources in CCE groups not used by the wireless device 300 a could beused for resources to other wireless devices 300 b. Hence, according toan embodiment any group of CCEs unused for resources for the wirelessdevice 300 a comprises at least one of resources and a control messagefor at least one other wireless device 300 b.

According to an embodiment the wireless device 300 a is operating with ashort TTI, and the control message is be a second control message,wherein the wireless device 300 a further receives a first controlmessage indicating a frequency band for the short TTI operation. Thefirst control message can be a slow DCI message and the second controlmessage can be a fast DCI message. The slow DCI message could be in acommon search space and the fast DCI could be in a device-specificsearch space.

A start position of a control message in a CCE group could be common tocontrol messages of different Aggregation Levels.

The wireless device 300 a could be the only wireless device receivingthe control message in a CCE group, or, the wireless device 300 a sharesthe CCE group with one or more further wireless devices 300 b.Additionally or alternatively, a plurality of wireless devices 300 a,300 b could share a CCE group to each receive an uplink grant.

FIG. 17 schematically illustrates, in terms of a number of functionalunits, the components of a network node 200 according to an embodiment.Processing circuitry 210 is provided using any combination of one ormore of a suitable central processing unit (CPU), multiprocessor,microcontroller, digital signal processor (DSP), etc., capable ofexecuting software instructions stored in a computer program product1010 a (as in FIG. 21), e.g. in the form of a storage medium 230. Theprocessing circuitry 210 may further be provided as at least oneapplication specific integrated circuit (ASIC), or field programmablegate array (FPGA).

Particularly, the processing circuitry 210 is configured to cause thenetwork node 200 to perform a set of operations, or steps, S102-S106, asdisclosed above. For example, the storage medium 230 may store the setof operations, and the processing circuitry 210 may be configured toretrieve the set of operations from the storage medium 230 to cause thenetwork node 200 to perform the set of operations. The set of operationsmay be provided as a set of executable instructions. Thus the processingcircuitry 210 is thereby arranged to execute methods as hereindisclosed.

The storage medium 230 may also comprise persistent storage, which, forexample, can be any single one or combination of magnetic memory,optical memory, solid state memory or even remotely mounted memory.

The network node 200 may further comprise a communications interface 220for communications at least with a wireless device 300 a, 300 b. As suchthe communications interface 220 may comprise one or more transmittersand receivers, comprising analogue and digital components and a suitablenumber of antennas for wireless communications and ports for wirelinecommunications.

The processing circuitry 210 controls the general operation of thenetwork node 200 e.g. by sending data and control signals to thecommunications interface 220 and the storage medium 230, by receivingdata and reports from the communications interface 220, and byretrieving data and instructions from the storage medium 230. Othercomponents, as well as the related functionality, of the network node200 are omitted in order not to obscure the concepts presented herein.

FIG. 18 schematically illustrates, in terms of a number of functionalmodules, the components of a network node 200 according to anembodiment. The network node 200 of FIG. 18 comprises a number offunctional modules; a transmit module 210 a configured to perform stepS104, and a transmit module 210 b configured to perform step S106. Thenetwork node 200 of FIG. 18 may further comprise a number of optionalfunctional modules, such as a transmit module 210 c configured toperform step S102. In general terms, each functional module 210 a-210 cmay be implemented in hardware or in software. Preferably, one or moreor all functional modules 210 a-210 c may be implemented by theprocessing circuitry 210, possibly in cooperation with functional units220 and/or 230. The processing circuitry 210 may thus be arranged tofrom the storage medium 230 fetch instructions as provided by afunctional module 210 a-210 c and to execute these instructions, therebyperforming any steps of the network node 200 as disclosed herein.

The network node 200 may be provided as a standalone device or as a partof at least one further device. For example, the network node 200 may beprovided in a node of the radio access network 110 or in a node of thecore network 120. For example, the network node 200, or at least itsfunctionality, could be implemented in a radio base station, a basetransceiver station, a NodeBs, an evolved NodeBs, an access points, oran access node. Alternatively, functionality of the network node 200 maybe distributed between at least two devices, or nodes. These at leasttwo nodes, or devices, may either be part of the same network part (suchas the radio access network 110 or the core network 120) or may bespread between at least two such network parts. In general terms,instructions that are required to be performed in real time may beperformed in a device, or node, in the radio access network 110.

Thus, a first portion of the instructions performed by the network node200 may be executed in a first device, and a second portion of the ofthe instructions performed by the network node 200 may be executed in asecond device; the herein disclosed embodiments are not limited to anyparticular number of devices on which the instructions performed by thenetwork node 200 may be executed. Hence, the methods according to theherein disclosed embodiments are suitable to be performed by a networknode 200 residing in a cloud computational environment. Therefore,although a single processing circuitry 210 is illustrated in FIG. 17 theprocessing circuitry 210 may be distributed among a plurality ofdevices, or nodes. The same applies to the functional modules 210 a-210c of FIG. 18 and the computer program 1020 a of FIG. 21 (see below).

FIG. 19 schematically illustrates, in terms of a number of functionalunits, the components of a wireless device 300 a, 300 b according to anembodiment. Processing circuitry 310 is provided using any combinationof one or more of a suitable central processing unit (CPU),multiprocessor, microcontroller, digital signal processor (DSP), etc.,capable of executing software instructions stored in a computer programproduct 1010 b (as in FIG. 21), e.g. in the form of a storage medium330. The processing circuitry 310 may further be provided as at leastone application specific integrated circuit (ASIC), or fieldprogrammable gate array (FPGA).

Particularly, the processing circuitry 310 is configured to cause thewireless device 300 a, 300 b to perform a set of operations, or steps,S202-S208, as disclosed above. For example, the storage medium 330 maystore the set of operations, and the processing circuitry 310 may beconfigured to retrieve the set of operations from the storage medium 330to cause the wireless device 300 a, 300 b to perform the set ofoperations. The set of operations may be provided as a set of executableinstructions. Thus the processing circuitry 310 is thereby arranged toexecute methods as herein disclosed.

The storage medium 330 may also comprise persistent storage, which, forexample, can be any single one or combination of magnetic memory,optical memory, solid state memory or even remotely mounted memory.

The wireless device 300 a, 300 b may further comprise a communicationsinterface 320 for communications at least with a network node 200. Assuch the communications interface 320 may comprise one or moretransmitters and receivers, comprising analogue and digital componentsand a suitable number of antennas for wireless communications and portsfor wireline communications.

The processing circuitry 310 controls the general operation of thewireless device 300 a, 300 b e.g. by sending data and control signals tothe communications interface 32 o and the storage medium 330, byreceiving data and reports from the communications interface 320, and byretrieving data and instructions from the storage medium 330. Othercomponents, as well as the related functionality, of the wireless device300 a, 300 b are omitted in order not to obscure the concepts presentedherein.

FIG. 20 schematically illustrates, in terms of a number of functionalmodules, the components of a wireless device 300 a, 300 b according toan embodiment. The wireless device 300 a, 300 b of FIG. 20 comprises anumber of functional modules; a receive module 310 a configured toperform step S206, and a receive module 310 b configured to perform stepS208. The wireless device 300 a, 300 b of FIG. 20 may further comprisesa number of optional functional modules, such as any of a receive module310 c configured to perform step S202, and a receive module 310 dconfigured to perform step S204. In general terms, each functionalmodule 310 a-310 d may be implemented in hardware or in software.Preferably, one or more or all functional modules 310 a-310 d may beimplemented by the processing circuitry 310, possibly in cooperationwith functional units 320 and/or 330. The processing circuitry 310 maythus be arranged to from the storage medium 330 fetch instructions asprovided by a functional module 310 a-310 d and to execute theseinstructions, thereby performing any steps of the wireless device 300 a,300 b as disclosed herein.

FIG. 21 shows one example of a computer program product 1010 a, 1010 bcomprising computer readable means 1030. On this computer readable means1030, a computer program 1020 a can be stored, which computer program1020 a can cause the processing circuitry 210 and thereto operativelycoupled entities and devices, such as the communications interface 220and the storage medium 230, to execute methods according to embodimentsdescribed herein. The computer program 1020 a and/or computer programproduct 1010 a may thus provide means for performing any steps of thenetwork node 200 as herein disclosed. On this computer readable means1030, a computer program 1020 b can be stored, which computer program1020 b can cause the processing circuitry 310 and thereto operativelycoupled entities and devices, such as the communications interface 320and the storage medium 330, to execute methods according to embodimentsdescribed herein. The computer program 1020 b and/or computer programproduct 1010 b may thus provide means for performing any steps of thewireless device 300 a, 300 b as herein disclosed.

In the example of FIG. 21, the computer program product 1010 a, 1010 bis illustrated as an optical disc, such as a CD (compact disc) or a DVD(digital versatile disc) or a Blu-Ray disc. The computer program product1010 a, 1010 b could also be embodied as a memory, such as a randomaccess memory (RAM), a read-only memory (ROM), an erasable programmableread-only memory (EPROM), or an electrically erasable programmableread-only memory (EEPROM) and more particularly as a non-volatilestorage medium of a device in an external memory such as a USB(Universal Serial Bus) memory or a Flash memory, such as a compact Flashmemory. Thus, while the computer program 1020 a, 1020 b is hereschematically shown as a track on the depicted optical disk, thecomputer program 1020 a, 1020 b can be stored in any way which issuitable for the computer program product 1010 a, 1010 b.

Examples of the disclosure describe transmitting information to thewireless device indicating at least one of the groups of CCEs comprisingresources for the wireless device. In further examples, the wirelessdevice determines the group of CCEs without receiving information, e.g.by a predetermined allocation or by determining from a parameter ofanother message.

References to aggregation level may refer to an aggregation level of asearch space (e.g. CSS, USS), aggregation levels of CCEs or anaggregation level of a control message (e.g. a control message formedfrom aggregated CCEs in a search space).

In some examples a slow grant may be considered as a control messagecomprising information of a frequency band for short TTI operation ofthe wireless device. In some examples, the slow grant may be consideredas a control message in a CSS, and/or the fast grant may be consideredas a control message in a USS. In some examples, a slow grant may beconsidered as control message transmitted once per subframe, and/or afast grant may be considered as a control message type which istransmitted (or uses a time resources which allows transmission) aplurality of times per subframe (e.g. once per wireless device in sTTIoperation served by a cell).

Any example of control message may also be referred to as a controlinformation message.

An LTE subframe lasting 1 ms contains 14 OFDM symbols for normal CP. ANew Radio (5G), NR, subframe may have a fixed duration of 1 ms and maytherefore contain a different number of OFDM symbols for differentsubcarrier spacings. An LTE slot corresponds to 7 OFDM symbols fornormal CP. An NR slot corresponds to 7 or 14 OFDM symbols; at 15 kHzsubcarrier spacing, a slot with 7 OFDM symbols occupies 0.5 ms.Concerning NR terminology, reference is made to 3GPP TR38.802 v14.0.0and later versions.

Aspects of the disclosure may be applicable to either LTE or NR radiocommunications. References to a short TTI may alternatively beconsidered as a mini-slot, according to NR terminology. The mini-slotmay have a length of 1 symbol, 2 symbols, 3 or more symbols, or a lengthof between 1 symbol and a NR slot length minus 1 symbol. The short TTImay have a length of 1 symbol, 2 symbols, 3 or more symbols, an LTE slotlength (7 symbols) or a length of between 1 symbol and a LTE subframelength minus 1 symbol. The short TTI, or mini-slot may be considered ashaving a length less than 1 ms or less than 0.5 ms.

The inventive concept has mainly been described above with reference toa few embodiments. However, as is readily appreciated by a personskilled in the art, other embodiments than the ones disclosed above areequally possible within the scope of the inventive concept, as definedby the appended claims.

The invention claimed is:
 1. A method for allocating resources to awireless device, the method comprising a network node: transmittingconfiguration information in a Radio Resource Control (RRC) message tothe wireless device configuring a search space for the wireless devicewith at least two groups of Control Channel Elements (CCEs), theconfiguration information in the RRC message including an indication ofunused CCEs within at least one group of CCEs available for sending userdata; transmitting a control message in one of the groups of CCEsavailable for sending the user data; transmitting a bitmap to thewireless device in Downlink Control Information (DCI) indicating unusedresources in one or more CCE groups that are allocated to the wirelessdevice for a data.
 2. The method of claim 1, wherein the configurationinformation indicates a size of each group of CCEs.
 3. The method ofclaim 1, wherein the configuration information only indicates groups ofCCEs not comprising the control message.
 4. The method of claim 1:wherein the control message is provided in one of the groups of CCEs;and wherein a further control message for the wireless device also isprovided in the one of the groups of CCEs.
 5. The method of claim 1,wherein only less than all of the groups of CCEs are allowed to comprisethe control message and/or the resources for the wireless device.
 6. Themethod of claim 1, wherein the configuration information is defined by abitmap.
 7. The method of claim 1, wherein each group of CCEs has a sizeto contain CCEs of at least two aggregation levels (AL).
 8. The methodof claim 7, wherein one of the at least two ALs is a maximum AL.
 9. Themethod of claim 1, wherein the resources are downlink resources.
 10. Themethod of claim 9, wherein the downlink resources are resources used fora short Physical Downlink Shared Channel (PDSCH).
 11. The method ofclaim 1, wherein the control message is a downlink assignment or anuplink grant.
 12. The method of claim 1, wherein: the control message isDownlink Control Information; the search space is a control channelcomprising CCEs; and/or the control channel is a physical downlinkcontrol channel.
 13. The method of claim 1, wherein any group of CCEsunused for resources for the wireless device comprises at least one ofresources and a control message for at least one other wireless device.14. The method of claim 1, wherein the configuration informationcomprises an indication of at least one of the groups of CCEs comprisingthe control message and/or a data message for the wireless device. 15.The method of claim 1, wherein the control message is specific to thewireless device.
 16. The method of claim 1: wherein the wireless deviceis operating with a short Transmission Time Interval (TTI), and thecontrol message is a second control message; wherein the wireless devicefurther receives a first control message indicating a frequency band forshort TTI operation.
 17. The method of claim 1, wherein a start positionof a control message in a CCE group is common to control messages ofdifferent Aggregation Levels.
 18. The method of claim 1, wherein thewireless device is the only wireless device receiving the controlmessage in a CCE group, or the wireless device shares the CCE group withone or more further wireless devices.
 19. The method of claim 1, whereina plurality of wireless devices share a CCE group to each receive anuplink grant.
 20. A method for receiving allocation of resources from anetwork node, the method comprising a wireless device: receivingconfiguration information in a Radio Resource Control (RRC) message fromthe network node configuring a search space for the wireless device withat least two groups of Control Channel Elements (CCEs) the configurationinformation in the RRC message including an indication of unused CCEswithin at least one group of CCEs available for sending user data;receiving a control message from the network node in one of the groupsof CCEs; and receiving a bitmap from the network node in DownlinkControl Information (DCI) indicating unused resources in one or more CCEgroups that are allocated for a data message.
 21. The method of claim20, wherein the configuration information indicates a size of each groupof CCEs.
 22. The method of claim 20, further comprising receivingconfiguration information indicating a start position of the resourceswithin the groups of CCEs.
 23. The method of claim 20, wherein thewireless device determines that resources in a CCE group containing thecontrol message for the wireless device, and which are unused for thecontrol message, comprise an allocation for a data message.
 24. Anetwork node for allocating resources to a wireless device, the networknode comprising: processing circuitry; and memory containinginstructions executable by the processing circuitry whereby the networknode is operative to: transmit configuration information in a RadioResource Control (RRC) message to the wireless device configuring asearch space for the wireless device with at least two groups of ControlChannel Elements (CCEs), the configuration information in the RRCmessage including an indication of unused CCEs within at least one groupof CCEs available for sending user data; transmit a control message tothe wireless device in one of the groups of CCEs; and transmit a bitmapto the wireless device in Downlink Control Information (DCI) indicatingunused resources in one or more CCE groups that are allocated for a datamessage.
 25. A wireless device for receiving allocation of resourcesfrom a network node, the wireless device comprising: processingcircuitry; and memory containing instructions executable by theprocessing circuitry whereby the wireless device is operative to:receive configuration information in a Radio Resource Control (RRC)message from the network node configuring a search space for thewireless device with at least two groups of Control Channel Elements(CCEs), the configuration information in the RRC message including anindication of unused CCEs within at least one group of CCEs availablefor sending user data; receive a control message in one of the groups ofCCEs; and receive a bitmap from the network node in Downlink ControlInformation (DCI) indicating unused resources in one or more CCE groupsthat are allocated for a data message.
 26. A method for allocatingresources to a wireless device, the method comprising a network node:transmitting configuration information via in a Radio Resource Control(RRC) signaling message to the wireless device configuring a searchspace for the wireless device with at least two groups of ControlChannel Elements (CCEs), the configuration information in the RRCmessage indicating a size of each group of CCEs; transmitting a controlmessage in one of the groups of CCEs; and transmitting a bitmap to thewireless device in Downlink Control Information (DCI) indicating unusedresources in one or more CCE groups that are allocated to the wirelessdevice for a data message.
 27. A method for receiving allocation ofresources from a network node, the method comprising a wireless device:receiving configuration information in a Radio Resource Control (RRC)message from the network node configuring a search space for thewireless device with at least two groups of Control Channel Elements(CCEs) the configuration information in the RRC message indicating asize of each group of CCEs; receiving a control message from the networknode in one of the groups of CCEs; and receiving a bitmap from thenetwork node in Downlink Control Information (DCI) indicating the unusedresources in one or more CCE groups that are allocated for a datamessage.